The present invention relates to an adjusting drive, and particularly to an adjusting drive with a drive motor and a worm transmission with a worm shaft formed on an extension of a motor armature shaft.
Adjusting drives of the above mentioned general type are known in the art. In a known adjusting drive a spherical running mushroom of a transmission shaft runs over a housing wall of the drive, which housing wall extends substantially at a right angle relative to the rotary axis of the transmission shaft. When the transmission shaft is rotated in the rotary direction under the action of full load so that the axial displacement applied to it is directed toward the housing wall, the pitch angle of the worm shaft in connection with the flank angle of the teeth of the worm shaft and the teeth of the worm wheel causes a load component which is directed transverse to the longitudinal axis of the worm shaft. This load component leads to a deviation of the worm shaft which results in changing the engaging condition in the worm transmission and thereby the driving characteristic of the adjusting drive in an undesirable manner.